Magnetic filter



March 10, 1959! D. c. VAREKAMP MAGNEHC' FILTSB Fle Dec. 9, 1954 v f 9 fi@ WWW/MW INVENTOR DIRK CORNELIS VAREKA M |illr.

MAGNETIC FILTER Dirk Cornelis Varekamp, Eindhoven, Netherlands, as-

signor, by mesne assignments, to North American Philips Company, Inc., New York, N. Y., a corporation of Delaware Application Deeember 9, 1954, Aseriell No. 474,171

Claims priority, application'Netherlands December 31, 1953 4 claims. (ci. 21o-223) The present invention relates to a magnetic filter device. More particularly, the invention relates to a magnetic filter comprising a preferably bipolar permanent magnet, which may be detachable and a number of polelpieces made from a material of high permeability between which the magnetic field for .capturing ferromagnetic particles to be filtered is produced. The invention has thev feature that the pole pieces are secured to a rotary member within a housing, through which the medium or fluid to be cleaned flows. The permanent magnet is provided outside the housing and insulated from lthe medium to be cleaned and the wall of the housing is furnished with one or more holes through which a cleaning medium is supplied in order to remove the captured particles through an outlet adapted to be closed. The magnet is arranged to be moved suciently away from the pole pieces to easily release the captured particles.- The poles of the magnet may be adequately short-circuited by means of a` member made from a material of high permeability.

The magnetic filter of the present invention has many advantages. First, the .constructiongmayl be such that by ar comparatively slight axial displacement of the permanent magnet, which is accessible from withoutthe` magnetic' eld between'the pole pieces' is weakened so that the captured particles are easily blown orwashed off and drained by the cleaning medium, for example air orwater supplied at a pressure. Second, the magnet is outside the housing through which the medium to be cleaned flows, so that the magnet itself remains clean, and dry'. The medium yto becleaned may comprise, for example, oil. Third, the rotary member together with the pole pieces may be mounted on a rotary shaft which is passed to the outside through the housing and driven, for example, by means of a lever or handwheel, so that all the pole pieces throughout the periphery of the rotary member are successively exposed to the stream of cleaning medium.

Preferably, the holes for the supply of cleaning medium are provided in such manner that the rotary member together with the pole pieces, also as a result of its shape, are driven by the cleaning medium. Magnetic lters of the type of the present invention are particularly suitable for considerable capacities of from 150 to 200 cubic meters per hour.

In order that the invention may be readily carried into effect it will now be described, by way of example, with reference to the accompanying drawing wherein:

Fig. 1 is a partial elevation and partial sectional view of an embodiment of the magnetic filter device of the present invention; and f Fig. 2 is a view taken along the lines II-II of Fig. 1.

In Fig. l, the cylindrical permanent magnet 1 is magnetised in an axial direction (arrow 2). At the poles provision is made of two pole plates 3 and 4; the plate 3 being provided with a ring 5 by means of which the magnet together with the plates 3, 4 can be lifted or moved axially. The magnet 1 is situated outside the housing through which the medium to be cleaned, for example 2 t oil, passes. The parts 3, 4, 7 and 8 are made from a material of high permeability, while the other parts of the housing and particularly the parts 6 and 9 are made from non-magnetic material. The parts 7, 8 are contiguous with the pole plates 3, 4, respectively, and conduct the magnetic flux within the housing. The parts 6, 9 of nonmagnetic material prevent the magnetic flux from being short-circuited. 1n the housing, pole pieces 13 (see also Fig. 2) made from undulated strip material, for example soft iron, are mounted on a member 11 which is rotatable about a shaft 10 and which comprises spokes 12. The pole pieces are arranged concentrieally about the magnet 1 between two soft iron pole plates 14, 15 supplying the ux to the pole pieces 13. The pole pieces 13 and the pole plates 14, 15 are positioned with interstices 16 therebetween and secured to a cylindrical member 17 of non magnetic material. The interstices 16 constitute the airgaps in which the ferro-magnetic particles from the medium to-be cleaned are captured and held. The magnetic flux through the filter is indicated by arrows 21. The pole plate 14 is furnished with holes 18 through which the medium to be cleaned ows (arrows 19) between the pole pieces and leaves the filter at its left-hand end. The outlet 20 is closed, for example by means of a closure device whichv is opened when it is desired to clean the filter.

At the top, the housing is provided with a hole accommodating a plug 22 which permits the rotary member with holes 18, prior to the operation of the filter, to be correctly positioned relative to the inlet and outlet ducts. The plug 22 may be a valve which is automatically closed e by means of a oat when the housing is filled.

If the filter is to be cleaned, the inlet and outlet of the filter are closed. The magnet 1 is lifted or axially moved, by means of the ring 5 so that the magnetic circuit isinterrupted and the particles collected in the gaps -16 are readily lre'leasable. Subsequently, the cleaning iluid outlet 20 is opened and the filter is emptied. Then a cock for the supply of cleaning medium, or fluid, such as for example, water, in ya tube 23 (Fig. 2) is opened. The tube 23 adjoins the housing and is provided with holes 24, 25.

The" holes"2'4are provided tangentially, the holes 25 ra, lSuch holes maybe providedthroughlut-` the,

dia h'eigli'tfof the housing. The holes 24 are preferably provided opposite the pole pieces 13 so that the rotary member 11 with pole pieces 13, in the form of a blade wheel, is driven in the direction of the arrow 27 by the Water jets from the said holes striking the pole pieces 13 tangentially. The holes 25 are provided opposite the air gaps 16 so that the latter are rinsed by streams of cleaning fluid from the said holes.

On the periphery of the housing of the filter, there may be provided, for example four tubes 23.

After emptying the filter by carrying off the cleaning fluid or water together with the captured particles along the inclined bottom 26, the cleaning fluid or water supply and the outlet 20 are shut olf. The magnet 1 may subsequently be placed in an axial direction andthe supply of medium to be cleaned may then be resumed to the filter.

What is claimed is:

1. A magnetic filter comprising a housing, a recess, outside said housing formed by said housing, a permanent magnet located in said recess, predetermined parts of said housing being constituted of material of high permeability, a plurality lof spaced pole pieces, means mounting said pole pieces in said housing for rotational movement for cleaning purposes only, the ferro-magnetic particles in said filter being captured in the space between said pole pieces by means of magnetic flux furnished by said permanent magnet and conducted through said predetermined parts of said housing and said pole pieces, means for supplying a medium to be cleaned to said pole pieces Patented Mar. 10, 19594 gemenecomprisingma-in. inlet and outlet -openingsinsaid housing, -f

side saidhousing formed by said housing, apermanent' magnet located in said recess, said permanent magnet having a= pair of pole plates, parts-of lsaid housing-icon# tii'guous-lwith said poleplates being constitutedv of material of" high permeability, other parts'ofl said Yhousingbeingconstituted .ofnon-magnetic material, a plurality ofspaced pole pieces, means mounting said pole `pieces in said.1

housing for rotational movement 'for'cleaning' purposes:

only; the ferromagnetic particles in said; 'lter 'being' :cap-- turedin the space between said pole pieces by means ot magnetic ux furnished by said permanent'magnet and'- conducted through said predetermined partsofsaid hous ing and said pole pieces, means for supplying amedium to be cleaned to said pole pieces comprising main inlet and outlet openings in said housing, and means for re-y moving the captured particles from said housing comprisingadditional inlet openings in said housingpositioned" to tangentially apply a cleaning medium 4to saidpole pieces;

and an additional outlet opening in the bottom of 'said` housing positioned to drain said `cleaningmedium` from the said housing, said pole mounting means beingrotait---l a'bly driven by said cleaning medium striking sai'df'pole pieces. v

3. A magnetic lter comprising a housing, a recess outa the saidvhousing, saidl pole mounting means being r'o'tat ably driven by. said Ycleaning medium striking said pole4 side said housing formed by said housing, a permanent magnet located in said recess, predetermined partsjof said' housing being constituted of material of high permeability, a plurality of spaced pole pieces, means'mountn'gu said pole vpieces in said housing for rotational movement for 'cleaning purposes only, the ferro-magneticpa'rticl'e's in"40 said filter being captured in the space between said pole pieces by means of magnetic flux furnished by said permanent'magnet andconducted through said predeter-iI mined parts of said housing and said 'pole pieces; means.. for supplying a medium to be cleaned` to said .pole pieces comprising-main inlet and outlet openings in. said housingmeans for removing -the -captured -particlesfromesaid' house ing comprising additional inlet openings in said housing positioned to apply a cleaning medium to said pole pieces and an additional outlet opening in the bottom of said housing positioned to drain saidcl'eaning medium from the said housing, a numberl of jsaidladditional inlet openings being Vpositioned to tangentially apply said cleaning mef diumftofsaid pole-'pices and th'eremaind'erof thesa'id additional inlet'opening's beingjp'o'sitioned to radially apply said 'cleaning medium to said pole pieces, said pole mounting means being rotatably driven by the tangentially directed cleaning medium striking said pole pieces.

4. A magnetic lter comprising a housing, a recess outside said housing formedfby said housing, a permanent magnet located in said recess, predetermined parts of said housing being constituted of material of vhigh permeability, a plurality of spaced pole pieces comprising a number of undulated! metallv strips positioned concentrically around saidfpermanent magnet, means mounting said pole pieces inxsaid` housing for rotational movement for cleaning pur` poses only, the ferro-magnetic particles in said lter being captured inthe A.space between said pole pieces by means of=magnetic .ux furnished by said permanent magnet and conducted through said predetermined parts of said hous-l gentially. apply a cleaning meduim to said' pole pieces and...anadditional outlet opening in the bottom of said housingl positioned lto drain said cleaning medium from pieces'.

References Cited in thele of this. patent UNITED STATESv PATENTS 2,317,774 Kiek etal Y Apr. 27, 1943 '21,398,725 Schutte Apr. 16, 194e 2,430,157 Byrd Nov. 4, 1 947 2732343. Hagberg Jan. 31,1956

y FOREIGN PATENTS '534,392 Great Britain Jan. 14. 

